Storms are driven by temperature, pressure and humidity gradients. If the Arctic warmed, these gradients would decrease and we would have fewer and weaker storms. If the Arctic was the same temperature as the equator, the Earth’s heat engine would turn off completely and there would be no storms, like on Venus.

Unilateral action by the U.S. would do nothing about the global stock and little about the global flow. China is now the biggest greenhouse-gas emitter on earth, and in developing nations, emissions are growing at an extraordinary rate. The Sophisticated Objection is that if the U.S. acts on its own, it will impose costs on the American people without seriously addressing the climate problem. What’s the point?